1/*	$NetBSD: adc.c,v 1.12 2009/04/30 05:20:30 nonaka Exp $ */
2
3/*
4 * Copyright (c) 2003 Valeriy E. Ushakov
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__KERNEL_RCSID(0, "$NetBSD: adc.c,v 1.12 2009/04/30 05:20:30 nonaka Exp $");
32
33#include <sys/param.h>
34#include <sys/kernel.h>
35#include <sys/device.h>
36#include <sys/malloc.h>
37#include <sys/systm.h>
38
39#include <sh3/adcreg.h>
40#include <sh3/dev/adcvar.h>
41
42#define ADC_(x)    (*((volatile uint8_t *)SH7709_AD ## x))
43
44
45static int	adc_match(device_t, cfdata_t, void *);
46static void	adc_attach(device_t, device_t, void *);
47
48CFATTACH_DECL_NEW(adc, 0,
49    adc_match, adc_attach, NULL, NULL);
50
51static int	adc_search(device_t, cfdata_t, const int *, void *);
52static int	adc_print(void *, const char *);
53
54
55static int
56adc_match(device_t parent, cfdata_t cf, void *aux)
57{
58
59	/* REMINDER: also in 7727 and 7729 */
60	if ((cpu_product != CPU_PRODUCT_7709)
61	    && (cpu_product != CPU_PRODUCT_7709A)
62	    && (cpu_product != CPU_PRODUCT_7706))
63		return (0);
64
65	if (strcmp(cf->cf_name, "adc") != 0)
66		return (0);
67
68	return (1);
69}
70
71
72static void
73adc_attach(device_t parent, device_t self, void *aux)
74{
75
76	ADC_(CSR) = 0;
77	ADC_(CR) = 0;
78
79	aprint_naive("\n");
80	aprint_normal("\n");
81
82	config_search_ia(adc_search, self, "adc", NULL);
83
84	/*
85	 * XXX: TODO: provide hooks to manage power.  For now register
86	 * null hooks which is no worse than before.
87	 *
88	 * NB: ADC registers are reset by standby!
89	 */
90	if (!pmf_device_register(self, NULL, NULL))
91		aprint_error_dev(self, "unable to establish power handler\n");
92}
93
94
95static int
96adc_search(device_t parent, cfdata_t cf, const int *ldesc, void *aux)
97{
98
99	if (config_match(parent, cf, NULL) > 0)
100		config_attach(parent, cf, NULL, adc_print);
101
102	return (0);
103}
104
105
106static int
107adc_print(void *aux, const char *pnp)
108{
109
110	return (pnp ? QUIET : UNCONF);
111}
112
113
114/*
115 * Sample specified ADC channel.
116 * Must be called at spltty().
117 */
118int
119adc_sample_channel(int chan)
120{
121	volatile uint8_t *hireg;
122	volatile uint8_t *loreg;
123	int regoff;
124	uint8_t csr;
125	int timo;
126#ifdef DIAGNOSTIC
127	uint8_t cr;
128	char bits[128];
129#endif
130	if ((chan < 0) || (chan >= 8))
131		return (-1);
132
133	regoff = (chan & 0x03) << 2;
134	hireg = (volatile uint8_t *)(SH7709_ADDRAH + regoff);
135	loreg = (volatile uint8_t *)(SH7709_ADDRAL + regoff);
136
137	/* the loop below typically takes 27 iterations on j680 */
138	timo = 300;
139
140#ifdef DIAGNOSTIC
141	csr = ADC_(CSR);
142	if ((csr & SH7709_ADCSR_ADST) != 0) {
143		/* another conversion is in progress?! */
144	        snprintb(bits, sizeof(bits), SH7709_ADCSR_BITS, csr);
145		printf("adc_sample_channel(%d): CSR=%s", chan, bits);
146		cr = ADC_(CR);
147		cr &= ~0x07;	/* three lower bits always read as 1s */
148	        snprintb(bits, sizeof(bits), SH7709_ADCR_BITS, cr);
149		printf(", CR=%s\n", bits);
150		return (-1);
151	}
152#endif
153
154	/* start scanning */
155	ADC_(CSR) = chan | SH7709_ADCSR_ADST | SH7709_ADCSR_CKS;
156
157	do {
158		csr = ADC_(CSR);
159		if (timo-- == 0)
160			break;
161	} while ((csr & SH7709_ADCSR_ADF) == 0);
162
163	/* stop scanning */
164	csr &= ~(SH7709_ADCSR_ADF | SH7709_ADCSR_ADST);
165	ADC_(CSR) = csr;
166
167	if (timo <= 0) {
168		printf("adc_sample_channel(%d): timed out\n", chan);
169		return (-1);
170	}
171
172	/*
173	 * 10 bit of data: bits [9..2] in the high register, bits
174	 * [1..0] in the bits [7..6] of the low register.
175	 */
176	return (((*hireg << 8) | *loreg) >> 6);
177}
178